During the term of project, April 1997 - March 1999 following research results have been obtained.I.Basic studies(1) Enhancement of therapeutic effect for the melanoma BNCT : Transfer of melanogenic gene, TRP-2 into less melanotic (pheomelanotic) human melanoma cells has enhanced their uptake of ^<10>B-BPA (Boronophenylalanine). Further, transfer of tyrosilase gene into fibroblast increased their uptake of ^<10>B-BPA.(2) Isolation and identification of novel-isoform for MITF gene which can regulate the expression of melanogenic genes. Identification of SRF which may regulate the expression of TRP-2.(3) Concerning mechanism of selective ^<10>B-BPA uptake into melanoma, we have found the formation of chemical complex between ^<10>B-BPA and melanin monomer/dimer, releasing lOB-boric acid which can be integrated melanin polymer formation.II.Development of devices and methods for gene and ^<10>B-BPA delivery.(1) Establishment of methodology to form transferrin-conjugate gene vector.(2) Form
… Moreulation method for nano-particle device as ^<10>B-BPA delivery carriers has proven its enhancing therapeutic effects in vovo.(3) Electroporation method has enhanced uptake of ^<10>B-compounds by target cells in vitro and in vivo.III.Therapeutic experiment using cancer-bearing animals.(1) After the tyrosinase-transfer into amelanotic melanoma cells in culture with subsequent subcutaneous transplantation of these cells into mouse, we have found the markedly enhanced killing effect of ^<10>B-BPA BNCT experiment.(2) After the in vivo tyrosinase gene-transfer into amelanotic melanoma proliferating in hamster skin by intra-tumor injection, we have found enhanced killing effect of ^<10>B-BPA BNCT in preliminary experiment.(3) Using i.v. injection of transfenin-conjugate of HSV-tk gene to tumor bearing mice, we have found its dstinct enhanced therapeutic effect prolonging their survival period.(4) After establishment of experimental model for amelanotic melanoma cells proliferating in brain, we have found increased ^<10>B-BPA uptake by these amelanotic melanoma cells, which were previously transfected with tyrosinase-gene, using ^<18>F-PET. Less